Welcome to Gryaab and the Rya Wastewater Treatment Plant. Here at the plant we receive wastewater from 8 municipalities in the Gothenburg region. After the water has been treated, it’s released in to the Gota estuary and flows to the sea.
Gothenburg is a city with population of 600 000 and is situated in the south west of Sweden, on both sides of the Gota estuary. Since 1621 Gothenburg has grown and developed into a modern industrialized city with a major port and home to industries such as Volvo and SKF.
In a time of rapid expansion for the city in the middle of the 1800’s sewer systems began to be built within the city, with the aim of limiting smell and the spread of disease by transporting wastewater and rain from the city center and into the estuary. This system was expanded and developed for the next century.
Besides the implementation of the sewers, the single largest development regarding wastewater handling and treatment within Gothenburg and its surrounding municipalities was the decision to collect and treat the wastewater. This was done by creating a system of tunnels to collect the wastewater and lead it to a large centralised regional wastewater treatment plant. To this end a company owned by the municipalities, Gryaab was created.
In 1972 The Rya WWTP was commissioned which included a tunnel system of 130 km, and relatively standard wastewater treatment facility serving a population equivalent of with requirement mainly for reduction of organic material to the estuary.
The Rya WWTP will soon be celebrating its 50th birthday and plenty has happened at the plant between the day of commissioning and now. Today the plant serves a population equivalent of 800 000 and has significantly more stringent discharge consents. The plant has been modified, rebuilt or retrofitted several times during the last five decades and today is a fully automated plant with an innovative combination of traditional processes such as activated sludge with more modern biofilm processes and disc filters for polishing of the effluent.
A large proportion of the combined sewers with the city of Gothenburg and some of the municipalities still exist which means that the plant has been developed to cope with times of high peak flows to the plant during heavy rainfall.
Looking toward the future, the population within the region is expected to grow, new municipalities may also connect to the system and more stringent discharge consents are also expected.
As a result of this, a project called New Rya has been initiated this year to look at potential solutions to our challenges. The project is expected to have four main phases and the expectation is that new treatment processes will be ready for action in 2036.